Bycatch and discards are a fact of life to a fisherman. There is no fishing method that catches only the quarry. ...The UN Food and Agriculture Organization estimates that about a third of what is caught worldwide, some 29 million tons, goes over the side. This takes what is hauled from the sea to around 132 million tons a year. Add to that the number of organisms that are killed or damaged by net, line, or trap and are never landed--such as whales, porpoises, turtles, and birds--and the number of animals destroyed on the bottom, and the total catch by fishermen reaches something more like 220 million tons a year. Consider that much of the weight of palatable fish is head, cartilage, bone, and offal, which goes over the side or is thrown away by processors. Consider also that about 44 million tons of fish are caught to make industrial products and food for farmed fish. Consider that some of the palatable fish caught will be turned into products for other than human consumption--as cat food, for instance. Consider that there may be an element of waste because some fish will not sell. Taking all these things into account, it is possible to conclude that the amount of protein eaten by someone or something is maybe less than 20 percent of the 104 million tons landed, and only 10 percent of the amount of marine animals destroyed annually in the oceans. These are rough figures, but, given a wide margin of error, they are about right. So catching wild fish is a wasteful business.
